Display screen or portion thereof having a graphical user interface



The FIGURE is a view of a display screen or portion thereof having a graphical user interface.

The dot-dashed broken lines depict a boundary of the display screen or portion thereof and form no part of the claimed design. The dashed broken lines depict portions of and environment of the display screen or portion thereof having a graphical user interface which form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof having a graphical user interface, as shown and described. 